Cutting blade for excavator



Sept. 17, 1963 w. ROCKWELL 3,103,752

CUTTING BLADE FOR EXCAVATOR Filed April 10, 1961 United States Patentice 3,103,752 CUTTING BLADE FOR EXCAVATOR Harvey W. Rockwell, CedarRapids, Iowa, assignor to Allis-Chalmers Manufacturing Company,Milwaukee, Wis.

Filed Apr. 10, 1961, Ser. No. 101,876 1' Claim. (Cl. 37-141) Thisinvention relates to a cutting blade 'for an excavator and particularlyto a cutting blade having an improved shearing action.

H'eretofore it has been suggested that teeth be installed on the cuttingedge of excavating machinery such as scrapers to improve the cuttingaction of the excavator. Such teeth are separate items which aredetachably installed on the scraper with resulting additional expense tothe user. The special digging teeth have facilitated excavating certaintypes of earth, however, it is desired to provide a cutting blade withimproved shearing action which can be standard equipment and not be ascostly to provide as a standard blade and detachable teeth. Heretofore,the straight blades which have been used in scrapers have requiredconsiderable power to shear the material being excavated, particularlywhen packed sand or clay is being excavated. It is an object of thisinvention to provide a blade which will give a slicing action in theprocess of shearing the material being excavated. Also it is an objectof this invention to provide a blade that is self-sharpening.

It is a further object of this invention to provide a blade for anexcavator which is not a special attachment such as a digging tooth, butrather is suitable for use as the standard blade for the excavator.

It is a further object of this invention to provide a blade of thehereinbefore mentioned character which is self-sharpening and whichmaintains its ability to produce a slicing action even when it has wornto a considerable extent.

It is a further object of this invention to provide a blade for a bowltype earth mover which breaks up the material being excavated therebyreducing the power required for loading and obtaining improved loadingaction in filling the bowl.

These and other objects of this invention will be ap parent when thefollowing description is read in conjunction with the drawings in which:

FIG. 1 is a top view of a scraper embodying this invention;

FIG. 2 is a side view of the scraper shown in FIG. 1 with a portion ofthe scraper broken away to show the attachment of the blade thereto;

FIG. 3 is a perspective view of the cutting blade attached to thescraper;

FIG. 4 is a top view of a blade per se;

:16. 5 is a front view of the blade shown in FIG. 4; an

FIG. 6 is an end view of the blade shown in FIG. 4.

Referring to FIGS. 1 and 2 a carry type scraper is illustrated. Thescraper 11 includes a yoke 12 having legs 13, 14 pivotally secured to abowl 16 on a transverse pivot axis 17. The rear end of the bowl 16 issupported by a pair of wheels 18, 19. An apron 21 and ejector 22 areprovided on the bowl to operate in a conventional manner. The ejector 22is mounted between a pair of side walls 23, 24 and above a bottom 26.The bottom 26 includes a longitudinal plate 27 and a box construction atthe forward end thereof for providing a blade supporting structure. Thebox construction includes :a transverse plate 28 welded to plate 27 anddisposed at an approximate 45 angle thereto and to the ground surface30. The box section is completed by a horizontal plate 29 3,103,752Patented Sept. 17, 1963 welded to plate 28 and a vertical plate 31 whichis welded to plates 29 and 27 to give a rigid construction.

My novel blade 32 is secured to plate 28 by a plurality of bolts 33 andnuts 34. Blade 32 is disposed at an acute vertical angle of inclinationto the direction of excavating movement 50. As illustrated in FIGS. 3and 4, taper headed bolts 33 extend through square openings 36 in blade32 and holes 37 in plate 28. In the illustrated embodiment of thisinvention four blades are utilized -for the cutting bottom portion ofthe wheeled scraper. These blades are disposed substantially at a righthorizontal angle to the direction of movement of the excavator duringexcavation. By using sectional portions of the blade, as illustrated,the forward edge of the bottom of the scraper may be laid out on aslight curve without requiring bending of the blade segments 32. Alsothe provision of several blade segments rather than a single blade forthe entire cutting edge permits low cost repair by replacing only thedamaged segment of the blade.

Referring now to FIGS. 3, 4, 5 and 6, the upper portion 42 of the blade32 is flat so as to facilitate attachment to the transverse plate 28.The lower portion of the blade 32 is corrugated as illustrated at 44,and terminates in a scalloped edge 45. The bottom surface 46 of blade 32is parallel to the direction of movementof the excavator which isparallel to surface 30 of the earth. The blade is self-sharpening and asit wears the scalloped cutting edge is maintained. For instance theblade may wear to the condition shown by dashed line 47 in FIGS. 3, 4and 6, and in such condition its edge will still have the desiredscalloped shape.

As shown in the top view of FIG. 1, the scalloped shape of cutting edge45 provides a horizontal angle a to the direction of cutting movementindicated by arrow 50 which produces a highly desired slicing actionsuch as that provided by the share of a mold'board plow. This slicingaction occurs over a substantial portion of the cutting edge.

The blade of this invention provides an unob-vious but desired result inthat the loading characteristics of a bowl type earth mover using such ablade are improved materially. The material passing from the corrugatedportion of the blade to the smooth portion of the blade tends to breakup in the transition from the uneven corrugated portion to the smoothportion. This crumbling of the excavated material produces easier andfuller loading of the bowl and mitigates the jamming or packing oflayers of excavated material which occurs in conventional earth moverswhen working in relatively cohesive earth for instance.

From the foregoing it is evident that applicant has pro vided a novelcutting blade for an excavator which is low in cost, and provides ahighly desired slicing action in its cutting operation. This blade maybe standard equipment rather than special equipment and will eliminatethe requirements for special cutting teeth to a considerable extent. Thecorrugated blade end not only provides a desired slicing action but isalso self-sharpening and maintains the scalloped or corrugated cuttingedge, even when worn to a considerable extent. Also the corrugatedportion of the blade serves a highly desired function of crumbling thematerial as it is cut. This occurs as the material passes from thecorrugated portion 44 to the flat portion 42.

Although a single embodiment of this invention has been illustrated anddescribed, it is not intended to limit this invention except asnecessitated by the scope of the appended claim.

What is claimed is:

In an excavator including a bowl having a horizontally disposed bottom,side walls extending upwardly from the bottom and a transverse supporton said bowl extending downwardly and forwardly of the forward end ofsaid bottom disposed at an acute vertical angle and substantially at aright horizontal angle to the direction of movement of the excavatorduring excavation, a blade having a flat upper portion and a corrugatedlower portion ter minating in a scalloped cutting edge, means securingsaid upper portion to said support whereby said blade is disposed at anacute vertical angle and substantially at a right horizontal angle tothe direction of movement of said excavator during excavation, and anend surface on said lower portion lying in a plane parallel to saiddirection of movement of said excavator during excavation, saidcorrugated portion constituting a substantial portion of said bladewhereby a scalloped cutting edge is maintained during the wearing awayof a substantial part of the lower portion of said blade.

References Cited in the file of this patent UNITED STATES PATENTS218,566 Peek Aug. 12, 1879 969,469 Gose Sept. 6, 1910 1,419,524 SeymsJune 13, 1922 1,741,933 Gunnison Dec. 31, 1929 1,765,218 Erhart June 17,1930 2,015,109 Hays Sept. 24, 1935 2,074,081 Burns Mar. 16, 19372,349,576 Daniels May 23, 1944 2,722,065 Smith Nov. 1, 1955 2,778,129Fryer Jan. 22, 1957 FOREIGN PATENTS 69,6 25 Sweden Feb. 18, 1928 807,036Germany June 25, 1951 92,888 Norway Sept. 20, 1958

